Account for the TrueNAS temperature gap before allowing disk standby

Bottom line: Include the temperature-observation gap in the disk power decision. Keep standby timing, APM idle behavior and the storage owner’s monitoring requirements as separate entries.

Source fact: what the authority says

The TrueNAS 25.10 Disks reference defines HDD Standby as an inactivity interval and uses Always On as its default. Temperature monitoring is disabled for disks in standby. The APM setting controls idle power-management behavior rather than maximum performance capability; actively accessed drives operate at full performance regardless of that setting. Bulk Edit Disks changes multiple disks together and lists the selected device names in Disks to be edited.

What the source does not establish

This article reviews a documented power and monitoring tradeoff, not drive qualification or a guarantee of energy savings. It does not equate an absent temperature reading with a healthy disk or prescribe a universal standby interval.

Applicability questions

• Which exact disks and workloads are included in the power-policy proposal?
• What standby interval and APM setting are currently configured?
• What temperature observations does the monitoring owner require?
• Who will review gaps and the actual effect of an approved isolated trial?

DSE recommendation: controlled next steps

The following steps are DSE recommendations based on the cited source.

DSE recommends documenting the monitoring requirement before selecting a standby interval. Ask the storage owner to decide whether the proposed temperature-observation gap is acceptable for the named disks. Keep that decision separate from a general desire to reduce power use, and do not claim a saving without a measured comparison.

Inventory the selected device names and current settings with a second operator. Review the installed-release procedure and the edit eligibility of the actual devices before applying a bulk change. Keep different drive populations and workload requirements distinct rather than approving every disk merely because the interface offers a shared selection.

Prepare an isolated trial with an owner-approved idle period and a harmless access workload. Record the expected monitoring observations and acceptable application behavior in advance. Treat standby timing and APM choice as separate variables so an unexplained change is not attributed to both settings without evidence.

Agree who investigates an unexpected temperature gap or workload interruption and who can restore the prior settings. Preserve the starting device list and configuration. Avoid interpreting a quieter monitoring display as an improved hardware condition, and keep drive health diagnosis within the separately reviewed storage process.

Verification and evidence

Proposed verification: inspect the selected disk identities and effective standby and APM settings against the plan. During the approved idle and access periods, retain the actual temperature observations and timestamps without supplying invented readings for gaps. Compare the harmless workload results with the owner’s written acceptance criteria.

Review the configured population again after any bulk edit and account for every selected device. Retain actual power measurements only if an appropriate separate measurement plan was performed. Have the storage and monitoring owners accept the observed tradeoff together, leaving unexplained gaps or device behavior open instead of prescribing a universal standby value.

Official references

• TrueNAS — Disks — official product documentation; confirm the installed release and configuration.

Source review completed October 30, 2026. Recheck the official documentation and deployment-specific applicability before a production change.